Facility environmental control systems often employ computer networks to perform management and control functions. Facility environmental control ("FEC") systems typically include an integrated collection of devices that monitor and affect the environment of a facility or building, including heating, venting, and cooling ("HVAC") equipment. Devices that monitor the environment, such as temperature sensors and the like, are referred to herein as measuring devices. Devices that affect the environment, such as heating and cooling equipment and the like, are referred to as controlled devices. One example of an FEC system is a common residential thermostat/furnace system. Such a system includes a thermostat for measuring the temperature and a circuit that controls the operation of the furnace, based on the measured temperature. FEC systems for large facilities include a substantial number of controlled devices and measuring devices.
In such large scale systems, control systems, which typically comprise one or more programmed computers, process and utilize the information received from the measuring devices to control the controlled devices. The control systems of advanced FEC systems not only regulate environmental conditions such as ambient temperature and humidity, but also the energy consumption of a facility. Consequently, FEC systems may monitor and control lighting, refrigeration, and other energy consuming equipment.
A requirement of a computer-based control system of a large scale FEC system is that it must be accessible by building management personnel in order to allow adjustment of environmental parameters. Environmental parameters include the desired ambient conditions of a facility such as, for example, the desired nighttime and daytime ambient temperature. To this end, the control system is typically provided with user interface software that allows the building management personnel to query measured conditions, query controlled device status, and alter system parameters.
Currently, computer-based FEC control systems employ software having proprietary program code, variable types, and data structures. As a result, all system software including the user interface software must ordinarily be provided by a single vendor. In such systems, referred to as closed systems, the customer is faced with a decision to either accept the vendor's standard user interface or negotiate a custom-designed interface to be developed by the vendor. Both approaches have disadvantages. In particular, while a standard vendor user interface may operate adequately, it may not have the same look and feel as the user interface of other computer systems in the customer's facility. As a result, the customer must train its employees to become familiar with new user interface configuration. With the proliferation of computer systems in the work place, each new user interface configuration adds undesirable complexity and training costs. In the alternative, requiring the FEC system vendor to provide a custom designed interface can introduce delays and often result in higher costs for at least the two following reasons. First, it is likely that the vendor does not possess expertise in user interface development techniques and therefore cannot efficiently develop new custom interface software. Second, to develop such software, the vendor must become familiar with the customer's user interface configurations.
One solution to the disadvantages discussed above is to allow the customer to design the user interface to suit his or her own requirements. A drawback to this approach is that the customer must become familiar with a significant amount of detail about the vendor system software including the proprietary program code, variable definitions, and data structures. Not only is the learning of such details time consuming and difficult, but furthermore vendors may prefer not to permit such access to their proprietary information.
A further disadvantage of single vendor closed systems is the lack of interoperability with the systems of other vendors. One consequence of having little or no interoperability is that if functionality is to be added to the FEC system at a later date, it must be provided by the same vendor. The result is highly constrained system flexibility and expandability.